Ink jet printing systems are known in which a printhead defines one or more rows of orifices which receive an electrically conductive recording fluid from a pressurized fluid supply manifold and eject the fluid in rows of parallel streams. Printers using such printheads accomplish graphic reproduction by selectively charging and deflecting the drops in each of the streams and depositing at least some of the drops on a print receiving medium, while others of the drops strike a drop catcher device.
Over the years, a number of inkjet printers using binary array continuous inkjet printing have been developed, with continuing improvements in speed, reliability, and ease of use. These printers are used in a variety of print applications, often using aqueous inks. Aqueous inks have a viscosity of approximately 1.0 cps and a surface tension of 42.0 dynes/cm. These inks create a uniform fluid film on the face of the catcher that is controlled and directed at a slot on the bottom of the catcher.
In spite of advances in aqueous ink technology, solvent inks, such as ethanol or MEK based inks, are preferred for some applications. For example, in applications such as printing on metals or plastics, solvent inks are preferred over aqueous inks as a result of the solvent ink characteristics of being much faster drying and more permanent than aqueous inks. Solvent inks, having a much lower surface tension (approximately 24 dynes/cm) create a fluid film on the face of the catcher that is much more difficult to control. As this film enters the throat of the catcher, the ink wicks up away from the throat creating a dripping effect during normal operation. This dripping of ink creates a need for an improved design that will eliminate the wicking of ink.
It is seen then that there is a need for an improved anti-wicking arrangement which overcomes the problems associated with the prior art.